Method and means for finishing siliceous articles



Oct; l22, 1935.-` Q DELPECH 2,018,056

METHOD AND MEANS FINISHING SILICEOUS ARTLCLESA xNvEN-roR A G'HSTON EL PEC/4 w It ATTO RN EYS G. DELPECH Oct. 212, 1935.

l METHOD AND MEANS FOR FINISHING SILICEOUS ARTICLES 2 sheets-sham 2 'Y Filed July .6,Y 1933 INVENTOR GASTON @EL PEcf/ BY v maf/,

ATTORNEYS Patented 22, 193s UNlTso1 STATES PATENT OFFICE METHOD AND MEANS FOR FINISHING SILICEOUS ARTICLES Gaston Delpech, Clamart, France, assignor to Societe Anonyme des' Manufactures des Glaces & Produits Chimiques de Saint-Gobain, Chauny 8s Cirey, Paris, France Application July 8, 1933, Serial No'. 679,207 y In France July 9, 1932 1o claims.

rials.

An object of this invention is to provide a simple and effective method of finishing hot articles immediately after they have been removed from the furnace.

Another object is the provision of means for removing the upper rough surfaces of a siliceous article in such a way as to prevent the formation of cracks in the underlying surfaces.

The above and other objects of this invention may be realized by a method of finishing siliceous articles, which comprises grinding or scraping the exterior surfaces of such articles, heating the treated surfaces in order to glaze them, and then reheating the articles. The articles are ground while they are still hot immediately after their removal from the furnace. The temperature ofthe exterior surfaces of these articles should be as high as possible and in any event should not fall below the so-called transformation point of cristobalite, which occurs at a temperature between 200 and 300. The exterior layers of the articles, which have rough and irregularly shaped surfaces, are completely removed in the course of this treatment. Due to the prevailing high temperature no cracks can be formed in the underlying layers, which consist of cristobalite. The ground surfaces are then heated to -a high temperature, i. e. to about l700, with the result that cristobalite-is transformed into molten silica and that the upper layers become fused, so that glazed-like surfaces are pro'- duced. The glazed articles are then reheated to a temperature of at least 1000 C. Particles of silica, which in the course of rst heating have.

'been evaporated and then condensed on the Vsur-l faces of the articles, are removed during the second heating. This double heat treatment tends to eliminate to a very large extent the inner strains developed within the articles inthe course of their manufacture. p

Suitable means for carrying out the abovedescrbed process, consist in agrinding device and a heating device adapted to be applied in rapid succession to the surfaces of a siliceous article. The article is preferably carried.by a movable support surrounded by a shell which supports the grinding and heating means operated from a convenient position outside of the shell.

In some instances, when the thickness of the articles is sumcient, the surfaces may be ground in the open, although the double heat treatment should be carried out while the article is covered by a shell.

The invention will appear more clearly from 5 the following detailed description when taken in connection with the accompanying drawing showing by Way of example an embodiment of the inventive idea.

In the drawing: 10

Figure 1 is a vertical section through a device constructed in accordance with the principles of the present invention.

Figure 2 is a section along the lines 2-2 of Figure 1 on a larger scale.

Figure 3 is a section along the line 3-3 of Figure 1 on a larger scale.

Figure 4 is a section along the line 4- 4 of Figure 1 on a larger scale.

'Ihe device illustrated in prises a metal shell 6, surrounding a hollowcylinder 1 made of a heat-insulating material. The inner surfaces of the cylinder 1 `are covered by a refractory coating 8. A plate 9 is iirmly con.- nected with the cylinder 1 and forms the bottom 25 closure of said cylinder. A ring I0, made of a refractory material, is situated on top of the cylinder 1 and is provided with a number of openings I I used for the passage of members forming a part of the grinding means I2. The ring I0 is 30 also provided with an opening I3, through which the heating device I4 passes into the interior of the ring I0. The hollow cylinder 1 and the ring I0 form a chamberl5. Another chamber I6 is situated above the chamber I5, and is formed by 36 l the walls of a cylinder I1 made of a heat-insulating material and firmly connected with a coverplate I8 provided with a central bore I9. The exterior side surfaces of the cylinder I1 are covered by a metallic shell 20, while the inner surfaces of the cylinder I1 are coated by a refractory lining 2|. The cylinder I1 is carried by a number of pieces 25, which are placed on top of the ring I0 at certain predetermined distances from each other so as to allow a free circulation of air 45 through the chambers I5 and I6 and a rapid removal of silica vapors produced in the course of the glazing process.

A threaded movable rod 22 passes through a" nut 23, which is rigidly connected with the plate 50 9. The upper end of the vertical rod 22 projects. into the chamber I5 and carries a plate 24, which is rotatable valong with the rod 22. A support 21, used for carrying anv article 28, is placed on top of the plate 24 and is rotated along with'this 55 the drawings com- 2Q portion 30.

threaded bore 32, is carried by the threaded porplate. A rod 29 is rigidly connected with the support 21 and is provided with an upper threaded The plate 3|, provided with an innerl tion 30 of the rod 29 and is adjustable along this threaded portion. Due to this arrangement, the article 28 may be securely clamped between the plate 21 and the plate 3 I A conical screen 33 carried by the threaded rod 22, is used for protecting the nut 23 and the upper portion of the rod 22 from sand and other particles, which 'may drop on the bottom of the chamber |5, while the article 281s being treated.

The threaded rod 22 carries a bevel gear 34, which is rotatable along with the rod 22. The gear 34 meshes with another gear 35 rigidly connected with a shaft 36 supported by a bracket 31. A pulley 38, which is driven by any suitable means, not shown in the drawings, is rigidly connected with a bevel gear 39, shown in Figure 3. In the position shown in Figure 3, two bevel gears 46 and 4I, which mesh with the bevel gear 39, are loosely carried by the shaft 36. A coupling 42, which may be operated by a. handle 43, shown in Figure l, is used for operatively connecting the shaft 36 with either the bevel gear 40 or the bevel gear 4|.

[gue to this arrangement, the direction of rotation of the rod 22 may be conveniently and quickly reversed. y

The grinding means I2, illustrated in Figures 1 and 2 `ofthe drawings, comprise three separate deviceseach'one of which projects through a separate opening formed in the ring I0. The three devices are preferably situated at different distances from the bottom of the chamber I 5.

i Since all the three devices I2 are substantially alike, vonly one of them will be described hereinafter.

The grinding device I2 comprises a grinding stone 45, which consists of quartz or silicon carbide and which is pivotally mounted on the forked end 46 of a lever 41. This end 46 is situated within the chamber I5. A support 48 is carried by the shell 6 and the cylinder 1. The two ends of a link 50 are pivotally connected with the lever 41 andthe support 48, respectively. One of the ends of a lever 5| is also pivoted in the support 48 and carries a pivot 52 passing through the outer end of the lever 41. 'I'he upper end of the lever 5| carries aweight 53, which is used for pressing the grinding stone 45 against the exter'ior surfaces of the article 28.

rlhe heating device I4 comprises three electrodes 55,56 and 51 (Figure 2), which are connected by wires 58, 59 and 60 to a -source of eleci trical energy, not shown in the drawings., The

electrodes 55, 56 and 51'are situated somewhat lower than the grinding devices I2 and project into the chamber. I5 throughl the opening I3 formed in the ring I0. The electrode 55 is carried by a. suitable socket 6 I while the electrodes 56 and 51 are carried by sockets 62 and 63, respectively. The socket 6| carrying the central electrode 55 is rigidly connected with the carriage 64, supported by wheels 65. The carriage 64 is movable along rails 66, which are carried by the shell Gand the cylinder 1. A pin 68 provided with a handgrip 69 passes through a plate 10, which ie rotatable along with the pin 68. A member 1| attached to the lower surface of the carriage 64, is used for carrying the pin 68. One of the ends of a link 12 is pivotally connected with the plate 10, while the other end of the link 12 is pivotally connected with another link 13. The opposite end of the iink i3 is rigidly connected with the socket 63, which carries the electrode 61. Another link 15 is also pivotally connected with the plate 10 and a link 16. The link 16 is rigidly connected with the socket 62 of the electrode 56. The handgrip 69, which is used for moving 5 the carriage 64, along the rails 66, may also be used for rotating the plate 10. Due to the provision of the links 12, 13, 15 and 16 a rotation of the plate 10 causes the projecting ends of the electrodes 5S and 51 to approach or to recede from 10 the immovable central electrode 55. Due to this arrangement the flame of the electrical arc bel tween these electrodes may be 'adjusted at will.

'Ihe device is operated as follows:

The driving means, not shown in the drawings, 15 are switched on and rotate the pulley 38. Then the lever 43 is manipulated to couple the shaft 36 with either the gear 4'0 or the gear 4| (Figure 3), depending on the direction of rotation of the pulley 38. The rotation of the shaft 36 is trans- 20 mitted through the gears 35 and 34 to the threaded rod 22. The rod 22 passing' through the nut 23 is caused to move upward, until the plate 24 reaches a level which is only somewhat lower than that of the grindstones 45. Then the lever 43 is 25 switched off and the hollowarticle 28 is placed on top of the plate 21. The plate 3| is moved along the rod 29 until it comes in contact with the upper edges ofthe article 28 and is pressed zgainst the article, which is then held tightly be- 30 tween the plates 21 and 3|. The cylinder I1 is then placed over,` the article 28 and on top ofthe supporting pieces 25 carried by the ring l0. The article 28 then occupies the position 'shown in broken lines in Figure l of the drawings'. Then 35 the lever 43 is switched inthe opposite direction with the result that the rotation of the shaft 36 is reversed, so that the threaded rod 22 begins to move downward; Each part of the exterior surfaces of the article 28 moves downward along a 40 helical line, and in the course of this movement, the exterior surfaces come in contact first with the three grinding devices I2. Immediately afterwardsthey are heated by the flame of the electric arc formed between the electrodes 55, 56 and 45 51. Due to this arrangement, the exterior surfaces of the article 28 are first ground and immediately afterwards glazed. This grinding and glazing process begins at the bottom of the article and gradually proceeds to the top thereof until 50 the entire article is treated. 'I'he article moves slowly downward from the position shown in broken lines in Figure 1, to the position shown in full lines in that figure. At that time the lever 43 is switched to the neutral position, so that the 55 rotation of the rod 22 is stopped. Then the operator swings the levers 5I in a direction away from the article 28 thus withdrawing the grindstones 45 from contact with the exterior surfaces of the armoe 2a. Then the1ever 4s is switched 6 on again so that the threaded rod 22 begins to ascend. I'he speed of the pulley 38 is increased with the result that the rod 22 and the article 28 carried by it move quite. quickly from the position shown in full lines in Figure 1 to the position shown in broken lines in the `same figure and beyond the last-named position. In the course'of this rapid movement, the flame which is produced by the arc, formed by the electrodes 55, 56 `and 70 51 removes allparts of the silica adhering to the. glazed surfaces. 'I'he current passing through the electrodes 55, 56 and 51 should be adjusted in such a'way that the article is heated to a temreheating process, which forms the last step of the described method, begins at the top of the article 28 and includes all the surfaces of the varticle to the bottom thereof. In the course `of the ascending movement, the article '2l is moved beyond the position which is shown in broken lines in Figure 1. 'I'he rod 22 is stopped when the upper portion 30 of the rod 29 has passed through the opening I9 formed in the cover Il. Then the opv prising grinding the surfaces of a hot siliceous article, said surfaces being maintained at a temperature which is at least equal to the transformation point of cristobalite, heating the ground sur-v faces while they are maintained at said temperature to`glaze the same, and then reheating the article. y

2. A method of treating siliceous articles. comprising'grinding the surfaces of a yhot siliceous article, said surfaces having a temperature which is at least equal to the transformation point'of cristobalite, simultaneously heating the ground surfaces while other surfaces are being ground,- and then reheating the article to a temperature which is at least equal to 1000 C.'

3. Means for treating siliceous articles,=com prising a support adapted to carry an article,

means connected with said support for reciprocating and rotating said support along with said article, a shell surrounding said support, heating means supported by said shell and adapted to'be applied to the surfaces of said article, means situated outside of said shell for adjusting said heating means, and grinding means adapted to be applied to the surface of said article.

4. Means for treating siliceous articles, comprising a support adapted to carry an article, means connected with said support for recipro-I eating and rotating said support along with said article, means surrounding said support and comprising a lower fixed shell, an upper removable shell, and means carried by the lower shell and supporting the upper shell; heating means supported by the lower shell and adapted to 'be applied to the surfaces of said article, means situated outside of said shell for adjusting said heating means, grinding means supported .by the lower shell and adapted 'to be applied to the surfaces of said article, and means situated outside of said shell for adjusting said grinding means.

5. Means for treating siliceous articles, comprising a support adapted to carry an article,- means connected with said support for recipro- Y mentioned step by eating .and rotating said support alongwithsaid article, means surrounding said support and comprising a lowerflxed shell. an upper remov- `able shell, a ring carried by said lower shell, and

a plurality of supporting pieces carried. by said 5 ring and carrying the upper shell, a vsupport connected to the outer surface of the lower shell, a grindstone adapted to be applied to the exterior surfaces of said article, a plurality of interconnected levers connecting said grindstone withsaid support, rails `connected to the outer surface of the lower shell, a carriage supported by'said rails, electrodes supported by said carriage and adapted to heat the exterior surfaces of said article, and means supported by said carriage for adjusting the relative position of said electrodes.

6. A method of treating siliceous articles, comprising grinding the surfaces of a hot siliceous article, said article being maintained at a temperature which is higher than the transformation point of cristobalite, glazing the surfaces, and then uniformly reheating the article to a temperature of at least 1000 C..

7. A method of treating siliceous articles, comprising maintaining a hot siliceous article at a' temperature' which is higher than the transformationv point of cristobalite, grinding the surfaces of said article during the first-mentioned step, then glazing these surfaces' during the lrst- 30 heatingtli'e same, and lthen reheating the article to a temperature of atleast 1000 C.

8. A method of treating siliceous articles, comprising grinding the surfaces of .a siliceous article while the temperature of said article is continuously maintained at a level which is higher than the transformationl point of cristobalite, glazing the ground surfaces of said article, and* uniformly reheating said article at a tempera- 40 ture of atleast 1000 C:E

9. A method of treating siliceous articles, com. prising grinding thesurfaces of a siliceous article while the temperature of said article is continuously maintained at a level which is higher than the transformation point ,of cristobalite, glazing the ground surfaces of said article, the temperature of said article being maintained at said level during the last-mentioned step, and uniformly reheating said article at a of said article is. i f 

